Re: [mpg123-users] Calling MPG123 from Asterisk, version behavior changed

[Thomas O. <tho...@or...>]

Am Fri, 10 Sep 2021 18:33:32 +0200
schrieb Carlos Oliva <car...@nu...>: 

> Investigating the issue, I discovered that with old versions of mpg123
> everything works. but with Debian package version (1.26.4-1) or las 1.29
> version I always hear noise.

Noise suggests that the sample encoding is different than expected.
> 
> mpg123 -q -s -b 96 -f 8192 --mono -r 8000 http://server.url/file.mp3 >
> out.sln
> 
> using mpg123 version 1.26 or 1.29 I get a file of 424K
> using mpg123 version 1.20.1 I get a file of 212K

So you got a 14-second-track here that should get you

	16 bit × 8000 Hz × 13.6 s = 212K

but you get twice that? I'd assume that mpg123 creates f32 or s32
output, then. Please look at the output without -q and -vv instead.

And yes … newer mpg123 does default to 32 bit float when the output
supports it. Your output is a pipe/file without any preferences. I see
that the current behaviour might be surprising and maybe it needs fixing.

> Is there any command line switch I can use for having the same output than
> in old version? I tried, but I couldn' t find how to make mpg123 work as

In any case, you can specify -e s16 for 16 bit integer encoding. This
works with mpg123 since ages now (I don't remember the exact version it
was introduced, but it was much longer ago than 1.20). When not playing
to a hardware device that prescribes encodings, it is best to be
specific, like with --mono.

Can you communicate that to the Asterisk folks in case they have
defaults that miss this?

At the same time, I am looking into whether it might be good to revert
to the old behaviour of s16 stereo as default format for writing to
files. 1.25.0 still worked that way. Since stable distros are slower to
picking up new versions, some more people could still be surprised.


Alrighty then,

Thomas